diff options
| -rw-r--r-- | compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs | 34 |
1 files changed, 1 insertions, 33 deletions
diff --git a/compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs b/compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs index 0043f0c7117..b38639ed8c6 100644 --- a/compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs +++ b/compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs @@ -390,45 +390,13 @@ fn check_predicates<'tcx>( let mut res = Ok(()); for (clause, span) in impl1_predicates { - if !impl2_predicates.iter().any(|pred2| trait_predicates_eq(clause.as_predicate(), *pred2)) - { + if !impl2_predicates.iter().any(|&pred2| clause.as_predicate() == pred2) { res = res.and(check_specialization_on(tcx, clause, span)) } } res } -/// Checks if some predicate on the specializing impl (`predicate1`) is the same -/// as some predicate on the base impl (`predicate2`). -/// -/// This basically just checks syntactic equivalence, but is a little more -/// forgiving since we want to equate `T: Tr` with `T: [const] Tr` so this can work: -/// -/// ```ignore (illustrative) -/// #[rustc_specialization_trait] -/// trait Specialize { } -/// -/// impl<T: Bound> Tr for T { } -/// impl<T: [const] Bound + Specialize> const Tr for T { } -/// ``` -/// -/// However, we *don't* want to allow the reverse, i.e., when the bound on the -/// specializing impl is not as const as the bound on the base impl: -/// -/// ```ignore (illustrative) -/// impl<T: [const] Bound> const Tr for T { } -/// impl<T: Bound + Specialize> const Tr for T { } // should be T: [const] Bound -/// ``` -/// -/// So we make that check in this function and try to raise a helpful error message. -fn trait_predicates_eq<'tcx>( - predicate1: ty::Predicate<'tcx>, - predicate2: ty::Predicate<'tcx>, -) -> bool { - // FIXME(const_trait_impl) - predicate1 == predicate2 -} - #[instrument(level = "debug", skip(tcx))] fn check_specialization_on<'tcx>( tcx: TyCtxt<'tcx>, |